Woodstock 50 is scheduled to take place from August 16-18 in Watkins Glen, New York, but the festival is facing uncertainty after former backers Dentsu Inc. pulled financial support from the festival back last month. At the time, Dentsu claimed that the festival was canceled, prompting founder Michael Lang to insist that the event will still take place.

Today, Lang sent a five-page letter to Dentsu (viewed by Pitchfork), which alleges that the former investors “illegally swept approximately $17 million from the festival bank account.” After claiming that the company was responsible for blocking ticket sales, Lang said that Dentsu suggested that performers, the venue, vendors, and others to cut ties with Lang.

“We also have evidence that Dentsu representatives have gone so far as to say that should the talent back out of Woodstock, they would be seen favorably by Dentsu and that this could result in their performing the 2020 Summer Olympics in Tokyo, where Dentsu is a major organizer,” Lang wrote. “In these actions too, Dentsu has acted not only without honor, but outside of the law.”

In the letter, Lang once again insists that the festival will continue as planned and claims that organizers have found “renewed interest in financing.” He asks that Dentsu return the $17 million and stop interfering with the festival going forward. “It is one thing if your company, Dentsu, wanted to back out of its commitment to Woodstock because it would not make as much money as it had hoped, but to try to suffocate and kill Woodstock so that we could not have a festival for our Golden Anniversary without you is puzzling for any company, let alone one that claims reform,” Lang wrote.

Woodstock 50’s lineup includes JAY-Z, the Killers, Dead & Company, Chance the Rapper, Miley Cyrus, the Raconteurs, and more. Pitchfork has reached out to Dentsu for comment.